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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>

        .box {
            width: 500px;
            background-color: #ff0;
            height: 100px;

            display: flex;
        }

        .a1 {
            width: 150px;
            border: 1px solid #000;
        }

        .a2 {
            border: 1px solid #000;
            /* overflow: hidden; */
            width: 350px;
        }

    </style>
</head>
<body>

    <!-- 
        弹性布局的特点2
            当弹性子元素没有写宽度的时候，宽度会一直被内容撑开(会超出父元素)   写固定宽度，要么加上overflow:hidden(最大只会占据剩余的宽度)
     -->

    <div class="box">
        <div class="a1">22</div>
        <div class="a2">111111111111111111111111111111111111111111111111111111111</div>
    </div>
    
</body>
</html>